Global Processes that Determine Cosmic Ray Modulation

The global processes that determine cosmic ray modulation are reviewed. The essential elements of the theory which describes cosmic ray behavior in the heliosphere are summarized, and a series of discussions is presented which compare the expectations of this theory with observations of the spatial and temporal behavior of both galactic cosmic rays and the anomalous component; the behavior of cosmic ray electrons and ions; and the 26-day variations in cosmic rays as a function of heliographic latitude. The general conclusion is that the current theory is essentially correct. There is clear evidence, in solar minimum conditions, that the cosmic rays and the anomalous component behave as is expected from theory, with strong effects of gradient and curvature drifts. There is strong evidence of considerable latitude transport of the cosmic rays, at all energies, but the mechanism by which this occurs is unclear. Despite the apparent success of the theory, there is no single choice for the parameters which describe cosmic ray behavior, which can account for all of the observed temporal and spatial variations, spectra, and electron vs. ion behavior.     

The SDI agreement between Bonn and Washington: Review of the first four years

This article provides an evaluation of the significance of the memorandum of Understanding (MOU) signed by the US and West German governments in March 1986. The author examines the expectations and fears it created in the FRG and compares them with the reality of actual economic benefit and exchange of information derived: the FRG's influence on arms control; and the effects on its standing and trading relations. The author argues that the MOU has had a negligible effect in securing contracts for West German firms and increasing technological cooperation, while damaging the FRG's standing in the arms control arena.     

Condensation reactions and formation of amides, esters, and nitriles under hydrothermal conditions

Hydrothermal pyrolysis experiments were performed to assess condensation (dehydration) reactions to amide, ester, and nitrile functionalities from lipid precursors. Beside product formation, organic compound alteration and stability were also evaluated. Mixtures of nonadecanoic acid, hexadecanedioic acid, or hexadecanamide with water, ammonium bicarbonate, and oxalic acid were heated at 300 degrees C for 72 h. In addition, mixtures of ammonium bicarbonate and oxalic acid solutions were used to test the abiotic formation of organic nitrogen compounds at the same temperature. The resulting products were condensation compounds such as amides, nitriles, and minor quantities of N-methylalkyl amides, alkanols, and esters. Mixtures of alkyl amide in water or oxalic acid yielded mainly hydrolysis and dehydration products, and with ammonium bicarbonate and oxalic acid the yield of condensation products was enhanced. The synthesis experiments with oxalic acid and ammonium bicarbonate solutions yielded homologous series of alkyl amides, alkyl amines, alkanes, and alkanoic acids, all with no carbon number predominances. These organic nitrogen compounds are stable and survive under the elevated temperatures of hydrothermal fluids.     

Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions

Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.     

The Evolution of the Anomalous Cosmic Ray Oxygen Spectra From 1995 to 1998: Ulysses Observations

Moraal and Steenberg (1999), showed that the peak energy in the anomalous cosmic ray spectra is independent of the radial distance up to a few AU away from the termination shock but dependent on the solar wind speed, the radius of the termination shock and the scattering strength. In this paper we will discuss the variation of the cosmic ray oxygen energy spectrum as measured by the Ulysses EPAC and the COSPIN/LET on board Ulysses. We found that the peak energy decreased from ∼5 MeV nucl⁻¹, when Ulysses was at high northern heliographic latitudes embedded in the fast solar wind to ∼3.5 MeV n⁻¹, in the streamer belt. The shift towards lower energy might also be caused by changing modulation although Voyager measurements indicate no variation of the ACR Oxygen spectrum at ∼60 AU. This revised version was published online in August 2006 with corrections to the Cover Date.